The present invention relates to an axle.
Driven axles for automotive vehicles are known whereby a drive shaft aligned generally longitudinally relative to the vehicle drives a pinion which is in meshing engagement with a crown wheel in an axle housing. The crown wheel drives a right hand drive shaft connected to a right hand wheel and also drives a left hand drive shaft connected to a left hand wheel, thereby propelling the vehicle. Typically, the crown wheel will drive the right and left hand drive shafts via a differential assembly.
Oil is provided in the axle housing for lubricating and cooling the crown wheel, a pinion, differential gears and associated bearings. However, the rotation of the crown wheel, the pinion and the differential housing in the oil leads to power losses due to oil churning, thereby increasing the overall fuel consumption of the vehicle.
U.S. Pat. No. 6,299,561 shows a crown wheel which, as it rotates, splashes oil over a wall of the associated housing. A hole in the lower portion of the wall allows oil to drain back to an area where it can again lubricate the crown wheel. However, the wall is a complicated structure to manufacture.
EP 1918613 shows a pre-fabricated shield fitted around at least a portion of the crown wheel. Oil is splashed out of the region around the crown wheel into another part of the axle housing, and the shield prevents the oil returning to a region where it can lubricate the crown wheel. A valve can be selectively opened to allow oil back into the region around the crown wheel under certain circumstances. However, the shield acts to isolate the crown wheel from other components in the axle including the axle tubes. In other words, the axle tubes are fluidly connected with a region outside the shield. In order to prevent excessive amounts of oil travelling down the axle tube, the oil level outside the shield is below a level of the bottom of an axle tube.